The white and mixed races, especially the former, constitute the property-owning and administrative classes, and naturally the Mexican upper class is drawn from these. The six million Indians, more or less, constitute some fifty aboriginal tribes in various stages of semi-civilisation or savagery, distributed all over the country from Sonora to Yucatan, and these are described elsewhere. It is not to be supposed that they are savages as a whole; for, on the contrary, they are remarkably gifted in some cases, assimilating the civilisation and intellect of the white man and furnishing excellent material for the country's citizens. The upper-class Mexicans, like the Peruvians or other Spanish-Americans when they are of unmixed white descent, naturally pride themselves upon the fact, and to a certain extent aim to preserve this condition. This is the "colour-line" of the race, and the term "Indio" is still a term expressing something of contempt, notwithstanding the fact that some of the prominent, and even intellectual, men of Mexico's history have been drawn from the Mestizo class, and--in the case of Juarez--from pure aboriginal stock. Of course, the Indian is, as yet, an inferior being. Included in Mexico's population is a foreign element numbering some 60,000 people, more or less, Spaniards predominating, with more than 16,000, and Americans of the United States with somewhat over 15,000. This is according to the census of 1900, and it is probable that both these elements have increased considerably since then. Of British there are only some 3,000 in the country; of French about 4,000; and of Germans 2,600, approximately. The vast area of Mexican territory contains only about twenty persons to the square mile; were it populated in the same ratio as parts of Europe it might support a population of 180,000,000, it has been calculated.